The formation of a Core Center for Skeletal Integrity is proposed within the Research Division of the Hospital for Special Surgery (HSS). The Center will be supported by NIH-sponsored investigators at HSS working in the area of bone development and repair, investigators for whom skeletal integrity (the biological, chemical and mechanical influences that make bone such a unique tissue) is a fundamental part of the research. Key to all the research questions is the relation between composition, structure, and function that allows the skeleton to fulfill its unique role. These three important factors control skeletal integrity and their measurement and evaluation are important across all disciplines, from molecular biology to biomechanics, and at all levels of tissue organization, from molecules to the whole organ. The Core Center is intended, therefore, to provide investigators with tools for establishing chemical composition, ultra- and microstructural morphology, and tissue and whole bone mechanical properties and with training to use these tools in their research efforts. Equally important, the techniques and scientific expertise within the Center will serve as a focal point for multi-disciplinary research, thus inspiring researchers to expand their investigations beyond their own field. The Center will consist of three research cores, Analytical Microscopy, Infrared Imaging, and Mechanical Testing, organized under an Administrative Core. The Center will provide investigators with access to shared techniques (and the necessary equipment and facilities to utilize them) and with training and technical support to perform these techniques. The Center will also initially support two Pilot and Feasibility grants from young investigators and provide them with technical support and with mentors to help in their research career development. Finally, the Center will conduct an enrichment program aimed at encouraging interaction and collaboration between core users and at informing investigators as they become available within the research cores.